Sliding contact arc suppression

ABSTRACT

A sliding power contact and method includes a mobile load device connector and a socket. The mobile load device connector includes a non-current power pin having a first length, a current power pin having a second length less than the first length, a neutral pin, and a ground pin. The socket includes a non-current power contact configured to electrically couple with the non-current power pin, a current power contact configured to electrically couple with the current power pin, a neutral contact configured to electrically couple with the neutral pin, and a ground pin configured to electrically couple with the ground pin. An arc suppressor is directly coupled to at least one of the non-current power pin and the non-current power contact, wherein the arc suppressor, the non-current power pin and the non-current power contact form a current path between the current power pin and the current power contact.

PRIORITY

This application is a continuation of U.S. patent application Ser. No.16/986,694, filed Aug. 6, 2020, which application is a continuation ofU.S. patent application Ser. No. 16/776,347, filed Jan. 29, 2020, issuedon Nov. 3, 2020 as U.S. Pat. No. 10,826,248, which application claimsthe benefit of priority to U.S. Provisional Application Ser. No.62/798,316, filed Jan. 29 2019; U.S. Provisional Application Ser. No.62/798,323, filed Jan. 29, 2019; and U.S. Provisional Application Ser.No. 62/798,326, filed Jan. 29, 2019, the contents of all which areincorporated herein by reference in their entireties.

TECHNICAL FIELD

The present application relates generally to sliding power contact arcsuppression.

BACKGROUND

Electrical current contact arcing may have a deleterious effects onelectrical contact surfaces, such as of relays and certain switches.Arcing may degrade and ultimately destroy the contact surface over timeand may result in premature component failure, lower qualityperformance, and relatively frequent preventative maintenance needs.Additionally, arcing in relays, switches, and the like may result in thegeneration of electromagnetic interference (EMI) emissions. Electricalcurrent contact arcing may occur both in alternating current (AC) powerand in direct current (DC) power across the fields of consumer,commercial, industrial, automotive, and military applications. Becauseof its prevalence, there have literally been hundreds of specific meansdeveloped to address the issue of electrical current contact arcing.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments are illustrated by way of example and not limitation inthe figures of the accompanying drawings.

FIG. 1 is a diagram of a sliding power contact, in an exampleembodiment.

FIGS. 2A-2F illustrate the predetermined sequence by which pinselectrically couple with their respective contact as a mobile loaddevice contact is inserted into a socket, in an example embodiment.

FIGS. 3A-3C are an abstract illustration of the predetermined sequencewith an electrically generic circuit diagram, in an example embodiment.

DETAILED DESCRIPTION

Sliding power contacts include electronic components known in the artand can include any structure in which contacts slide with respect toone another rather than directly separating from one another, as in aswitch. Such sliding power contacts may include, but are not limited to,components such as electrical cords, such as may be found inconventional appliances, power outlets, generators, charging stations,such as for electronic devices, electric vehicles, and the like, and anyof a variety of examples of machinery the use of which involves frequentconnections and disconnections. Such sliding power contacts may ofteninclude, a stationary socket, such as a jack, and a mobile load deviceconnector, such as a plug that is coupled to or within the socket. Asthe mobile load device connector is coupled to the socket the electricalcontacts slide with respect to one another, creating the conditions forarcing.

Arc suppressors can utilize contact separation detectors to detect aseparation in the sliding contacts and/or a closing of the slidingcontacts based on sudden changes in the voltage over the contacts. Thecontact separation detector may cause a contact bypass circuit to openin order to allow current to bypass the contacts during the transitionperiod. However, transition period may not, and in many cases does not,include a simple and efficient voltage transition. Rather, a series ofvoltage bounces may occur as the electrical contacts open or close,causing small arcs or “arclets” to form. These arclets may damage thecontacts even if a primary arc is suppressed.

Systems and methods have been developed to utilize arc suppressors tosuppress arc formation at the earliest stages in sliding power contactand any related situation. For instance, in addition to sliding powercontacts, the principles disclosed herein apply as well to circumstancesin which differently-charged pieces of metal slide with respect to oneanother. For instance, the catenary wires, so-called third-rail systemsas seen on subways and the like, and motor brushes all createcircumstances in which contacts slide with respect to one another, andat the time of contact an arc may be created between the contacts.

FIG. 1 is a diagram of a sliding power contact 100, in an exampleembodiment. The sliding power contact 100 includes a socket 102 and amobile load device connector 104, such as a plug. The mobile load deviceconnector 104 includes a non-current power pin 106 having a firstlength, a current power pin 108 having a second length, a neutral pin110 having a third length, and a ground pin 112 having a fourth length.The socket 102 includes a non-current power contact 114 configured toengage and electrically couple with the non-current power pin 106, acurrent power contact 116 configured to engage and electrically couplewith the current power pin 108, a neutral contact 118 configured toengage and electrically couple with the neutral pin 110, and a groundcontact 120 configured to engage and electrically couple with the groundpin 112.

As depicted, the fourth length is longer than the first, second, andthird lengths the third length is longer than the first and secondlengths and the first length is longer than the second length. As aconsequence, the mobile load device connector 104 is configured suchthat when the mobile load device connector 104 is inserted into thesocket 102 the pins 106, 108, 110, 112 electrically couple with theirrespective contact 114, 116, 118, 120 in a predetermined sequence. Inparticular, the predetermined sequence may be that the ground pin 112electrically couples to the ground contact 120 first, the neutral pin110 electrically couples to the neutral contact 118 second, thenon-current power pin 106 electrically couples to the non-current powercontact 114 third, and the current power pin 108 electrically couples tothe current power contact 116 fourth.

The sliding power contact 100 includes an arc suppressor 122electrically coupled to the non-current power pin 106 and between thenon-current power pin 106 and the current power pin 108. The arcsuppressor 122 may be any suitable arc suppressor known or in the art orthat may be developed, e.g., as disclosed in U.S. Pat. No. 8,619,395,TWO TERMINAL ARC SUPPRESSOR, Henke, filed Mar. 12, 2010, U.S. Pat. No.9,423,442, ARC SUPPRESSOR, SYSTEM, AND METHOD, Henke, filed Sep. 27,2013, U.S. Patent Application Publication No. 2014/0334050, PASSIVE ARCSUPPRESSOR, Henke, filed May 7, 2014, all of which are incorporated byreference herein in their entirety, as well as other arc suppressorsincorporated by reference herein. The arc suppressor 122, in conjunctionin various examples with the predetermined sequence of pins and contactselectrically coupling with one another disclosed above, may suppressarcing between the pins 106, 108, 110, 112 and contacts 114, 116, 118,120, as disclosed in detail herein.

In such examples, ordinarily the arc suppressor 122 is in an open stateand current does not flow between the non-current power pin 106 andnon-current power contact 114. As such, current is left to flow over thecurrent power pin 108 and current power contact 116 if in contact withone another or not flow if the current power pin 108 and current powercontact 116 are not in contact with one another. However, if and whenthe current power pin 108 and current power contact 116 come intocontact with one another an the conditions exist for arcing between thepin 108 and contact 116, then the arc suppressor 122 detects thecondition for an arc and opens a path for current briefly to flow overthe non-current path created by the non-current power pin 106 andnon-current power contact 114. As such, it is to be recognized andunderstood that “non-current” for the purposes of this disclosure doesnot literally mean no current ever flows over such a non-current pathcreated by the non-current pin 106, the non-current contact 114, and thearc suppressor 122. Rather, current rarely flows over the non-currentpath and, in various examples, only when the arc suppressor isrelatively briefly shunting the current away from the current power pin108 and current power contact 116 in the course of suppressing arcing.

For the purposes of this disclosure, it is to be recognized andunderstood that the term “length” does not necessarily mean an absolutelength of the pins 106, 108, 110, 112 and contacts 114, 116, 118, 120,e.g., a distance from a first end 124 to a second end 126 of a pin 112.Rather, length may refer to an apparent length of the pins 106, 108,110, 112 and contacts 114, 116, 118, 120. For instance, for the pins106, 108, 110, 112, length may be an apparent length based on a distanceto an edge 128 of the mobile load device connector 104 or, stateddifferently, a pin 106, 108, 110, 112 having the greatest distance fromits second end 126 to the edge 128 may be considered to have theshortest length while the pin 106, 108, 110, 112 having the shortestdistance from its second end 126 to the edge 128 may be considered tohave the longest length.

FIGS. 2A-2F illustrate the predetermined sequence by which the pins 106,108, 110, 112 electrically couple with their respective contact 114,116, 118, 120 as the mobile load device contact 104 is inserted into thesocket 102, in an example embodiment. While the predetermined sequenceis illustrated with respect to the sliding power contact 100, it is tobe recognized and understood that the principles disclosed herein mayapply to any suitable sliding power contact, including sliding powercontacts that do not have the same number of pins 106, 108, 110, 112 andcontacts 114, 116, 118, 120 and/or the same illustrated configuration.

FIG. 2A illustrates the sliding power contact 100 without any pins 106,108, 110, 112 and contacts 114, 116, 118, 120 electrically coupled toone another.

FIG. 2B illustrates the mobile load device contact 104 partiallyinserted into the socket 102 such that the ground pin 112 makes initialcontact with the ground contact 120.

FIG. 2C illustrates the mobile load device contact 104 partiallyinserted into the socket 102 such that the neutral pin 110 makes initialcontact with the neutral contact 118 while the ground pin 112 is furtherseated in the ground contact 120.

FIG. 2D illustrates the mobile load device contact 104 partiallyinserted into the socket 102 such that the non-current power pin 106makes initial contact with the non-current power contact 112 and theneutral pin 110 and ground pin 12 are further seated in the neutralcontact 118 and ground contact 120, respectively. The contacting of thenon-current power pin 106 with the non-current power contact 112electrically couples the arc suppressor 122 to the socket 102 generally.

FIG. 2E illustrates the mobile load device contact 104 partiallyinserted into the socket 102 such that the current power pin 108 makesinitial contact with the current power contact 116, while thenon-current power pin 106, neutral pin 110, and ground pin 112 arefurther seated in the non-current power contact 114, the neutral contact118, and ground contact 120, respectively. Owing to the arc suppressor122 already having been coupled via the non-current power pin 106 andcontact 114, the arc suppressor 122 suppresses any arcing that mighttend to occur between the current power pin 108 and current powercontact 116 as those components draw near to one another and eventuallycontact one another.

FIG. 2F illustrates the mobile load device contact 104 fully insertedinto the socket 102.

It is to be recognized and understood that withdrawing the mobile loaddevice contact 104 from the socket 102 repeats the predeterminedsequence in reverse, with each step defining a breaking of the pin 106,108, 110, 112 from its respective contact 114, 116, 118, 120 and withthe arc suppressor 122 suppressing the arc that would be expected toresult from the breaking of the current power pin 108 from the currentpower contact 116.

FIGS. 3A-3C are an abstract illustration of the predetermined sequencewith an electrically generic circuit diagram, in an example embodiment.For the purposes of this discussion, the generic circuit diagram will bedescribed with respect to a sliding power contact 200. However, as willbe described in detail below, the generic circuit diagram may describeany situation in which two contacts, wires, electrodes, or any othersuitable electronic component or article slide in contact with oneanother, such as with a commutator in a motor or catenary system orchafing wiring.

The sliding power contact 200 includes a socket 202 and a mobile loaddevice connector 204. The mobile load device connector 204 includes anon-current power pin 206, a current power pin 208, a neutral pin 210,and a ground pin 212. The socket 202 includes a non-current powercontact 214 configured to engage and electrically couple with thenon-current power pin 206, a current power contact 216 configured toengage and electrically couple with the current power pin 208, a neutralcontact 218 configured to engage and electrically couple with theneutral pin 210, and a ground contact 220 configured to engage andelectrically couple with the ground pin 212.

The predetermined sequence for the sliding power contact 200 is similarto and operates under the same principles as the predetermined sequenceapplying to the sliding power contact 100, with two implementationaldifferences. First, the arc suppressor 222 is a component of the socket202 rather than the mobile load device connector 204. As such, the arcsuppressor 222 is directly coupled to the non-current power contact 216and, when the sliding power contact 200 is coupled together, creates anon-current path with the non-current power contact 214 and thenon-current pin 206.

Second, the non-current power pin 206, the neutral pin 210, and theground pin 212 have a first length that is approximately the same lengthwhile the current power pin 208 has a second length shorter than thefirst length. For the purposes of this disclosure, the first lengthbetween and among the non-current power pin 206, the neutral pin 210,and the ground pin 212 may vary by several percent but may be consideredapproximately the same length nonetheless provided that all of thenon-current power pin 206, the neutral pin 210, and the ground pin 212contact their respective contacts 214, 218, 220 before the current powerpin 208 contacts the current power contact 216. Consequently, thepredetermined sequence involves the simultaneous or near-simultaneouscontacting of the non-current power pin 206, the neutral pin 210, andthe ground pin 212 contact their respective contacts 214, 218, 220followed by the contacting of the current power pin 208 with the currentpower contact 216.

FIG. 3A illustrates the sliding power contact 200 in a disconnectedconfiguration.

FIG. 3B illustrates the sliding power contact 200 in an initialconnected configuration. In the initial connected configuration, thenon-current power pin 206, the neutral pin 210, and the ground pin 212are in contact with their respective contacts 214, 218, 220 while thecurrent power pin 208 is not in contact with the current power contact216. The arc suppressor 222 is thereby electrically coupled over thenon-current power pin 206 and the non-current power contact 214, and isprepared to suppress arcing upon the current power pin 208 contactingthe current power contact 214.

FIG. 3C illustrates the sliding power contact 200 in a fully connectedconfiguration. All of the pins 206, 208, 210, 212 are connected to theirrespective contacts 214, 216, 218, 220. The previous inclusion of thearc suppressor 222 into the system suppresses any arcing that may haveoccurred between the current power pin 208 contacting the current powercontact 214.

As with the predetermined sequence for the sliding power contact 100, itis to be recognized and understood that withdrawing the mobile loaddevice contact 204 from the socket 202 repeats the predeterminedsequence in reverse, with each step defining a breaking of the pin 206,208, 210, 212 from its respective contact 214, 216, 218, 220, and withthe arc suppressor 222 suppressing the arc that would be expected toresult from the breaking of the current power pin 208 from the currentpower contact 216.

While the arc suppressors 122, 222 are disclosed as being located in asingle location, it is to be recognized and understood that in each ofthe sliding power contacts 100, 200, the arc suppressor 122, 222 may belocated in either the socket 102, 202, or the mobile load deviceconnector 104, 204, or both, e.g., a separate arc suppressor 122, 222may be implemented in both the socket 102, 202, and the mobile loaddevice connector 104, 204. Moreover, components of a single arcsuppressor 122, 222 may be split between the socket 102, 202 and themobile load device connector 104, 204, with the connecting of thenon-current power pin 206 to the non-current power connector 214 causingthe components of the arc suppressor 122, 222 to be electrically coupledto one another and form the functional arc suppressor 122, 222 upon thecoupling of the non-current power pin 206 to the non-current powerconnector 214.

While pins 106, 108, 110, 112, 206, 208, 210, 212 and contacts 114, 116,118, 120, 214, 216, 218, 220 are described herein, it is to berecognized and understood that any situation in which contacts slidewith respect to one another may create the circumstances for arcing andmay be electrically represented in the same manner as the sliding powercontacts 100, 200. Thus, principles disclosed with respect to thesliding power contacts 100, 200 may be applied to any of a variety ofother circumstances that do not only involve pins and contacts. Forinstance, a catenary or overhead wire system includes a charged contactwire and a current collector placed, e.g., on the top of a train andpressed against and slides along the charged contact wire. A third-railtrain includes a charged contact rail and a current collector placedagainst the charged contact rail. In various examples, such a system mayincorporate a commutator to make the connection with the charged contactwire, or the charged contact more generally. Additional uses of acommutator include as a rotating sliding power contact that may provideelectrical continuity and conductivity between a motor/generator statorand a motor/generator rotor. For the purposes of equating the additionalsystems to the existing labels of FIGS. 3A-3C, a charged contact, suchas a charged contact wire or charged contact rail, may be consideredequivalent to a current power contact 116 while, e.g., a currentcollector or commutator may be considered equivalent to the currentpower pin 108.

In such an example, as an electrical circuit, the commutator may havethe same electrical function as the mobile load device connector 204 andthe stator and/or rotor may have the same electrical function as thesocket 202, or vice versa. By incorporating a non-current power linethat is coupled to an arc suppressor 222 and which is configured toprovide an electrical connection between the commutator and the statorand/or rotor before the current power line makes contact, arcing may besuppressed during the operation of the motor or catenary line, as thecase may be. Thus, the diagrams of FIGS. 3A-3C, while specifically drawnto a sliding power contact, may be understood to be electricallyrelevant to any situation with power contacts that slide with respect toone another. In circumstances with a commutator, brush motor, or otherhigh speed rotational contact, a high speed arc suppressor asincorporated by reference herein may be utilized.

Similarly, wires that chafe and wear through insulation may createsliding contacts that may be susceptible to arcing. For instance, in acircumstance in which two wires rub against one another and wear awaytheir insulation at the point of contact, eventually the bare wires maycome into contact in a sliding relationship and cause arcing. In such anexample, either as protection against arcing or as a wire chafingdetector, an arc suppressor 222 may be coupled as part of a non-currentpower line between the two wires prior to chafing, e.g., at the time ofinstallation.

Once mechanical motion has worn through both insulations, therebyexposing the bare conductor on either side, an unintentional contact iscreated which follows the same physics, rules and principals than anyother intentional contact consisting of two opposing electrodes duringwhich, when connected, a current flows. When the two exposed wireconductors make unintentional contact, an arc may be created. In such anexample, one wire may be electrically the same as the current power pin208 and the other wire may be electrically the same as the current powercontact 216. In such an example, the inclusion of the arc suppressor 222in parallel with the wires may create a non-current path between thewires which would provide arc suppression in the event that the wireschafed and eventually contacted one another.

Moreover, given that the arc suppressor 222 may include visual or signaloutputs to indicate that arcing has occurred, the inclusion of the arcsuppressor 222 may provide for chafing detection. As the arc suppressor222 in such a circumstance would only suppress an arc following chafingbetween the wires, the occurrence of the arc suppressor 222 indicatingthat an arc had been suppressed could be identified as an indicationthat the wires had chafed and shorted together. Thus, it is to berecognized and understood that the non-current path may be effectivelypermanent or at least resilient while the current path may be createdfollowing the wires chafing and shorting together.

ADDITIONAL EXAMPLES

The description of the various embodiments is merely exemplary in natureand, thus, variations that do not depart from the gist of the examplesand detailed description herein are intended to be within the scope ofthe present disclosure. Such variations are not to be regarded as adeparture from the spirit and scope of the present disclosure.

Example 1 is an arc suppressing circuit configured to suppress arcingacross a power contactor coupled to an alternating current (AC) powersource having a predetermined number of phases, each contact of thepower contactor corresponding to one of the predetermined number ofphases, the arc suppressing circuit comprising: a number of dualunidirectional arc suppressors equal to the predetermined number ofphases of the AC power source, each dual unidirectional arc suppressorcoupled across the power contactor, each dual unidirectional arcsuppressor comprising: a first phase-specific arc suppressor configuredto suppress arcing across the associated contacts in a positive domain;a second phase-specific arc suppressor configured to suppress arcingacross the associated contacts in a negative domain; and a coil lockcontroller, configured to be coupled between a contact coil driver ofthe power contactor, configured to detect an output condition from thecontact coil driver and inhibit operation of the first and secondphase-specific arc suppressors over a predetermined time.

In Example 2, the subject matter of Example 1 includes, wherein thefirst phase-specific arc suppressor is configured to not suppress arcingin the negative domain and the second phase-specific arc suppressor isconfigured to not suppress arcing in the positive domain.

In Example 3, the subject matter of any one or more of Examples 1 and 2includes, wherein each of the first and second phase-specific arcsuppressors comprise a latching switch configured to cause the first andsecond phase-specific arc suppressors to not suppress arcing in thenegative and positive domains, respectively.

In Example 4, the subject matter of any one or more of Examples 1-3includes, wherein the latching switch is a thyristor.

In Example 5, the subject matter of any one or more of Examples 1-4includes, wherein the coil lock controller comprises: a power convertercoupled over a coil interface; a rectifier coupled to the powerconverter; a power limiter coupled to the rectifier; a power storagecoupled to the power limiter; and a current supply coupled to the powerstorage, the current supply coupled to the first phase-specific arcsuppressor and the second phase-specific arc suppressor.

In Example 6, the subject matter of any one or more of Examples 1-5includes, wherein the power converter comprises an RC circuit, therectifier comprises a diode array, the power limiter comprises a Zenerdiode; the power storage comprises a capacitor; and the current supplycomprises a MOSFET transistor.

In Example 7, the subject matter of any one or more of Examples 1-6includes, wherein each of the first and second phase-specific arcsuppressors comprise a coil lock, coupled to the coil lock controller,configured to disable a respective one of the first and secondphase-specific arc suppressors based on an input from the coil lockcontroller.

In Example 8, the subject matter of any one or more of Examples 1-7includes, wherein the coil lock comprises a signal isolator emittercoupled to the coil lock controller and a signal isolator detectorcoupled to the latching switch.

In Example 9, the subject matter of Example 8 includes, wherein the coillock is a photorelay comprising the signal isolator emitter and thesignal isolator detector.

In Example 10, the subject matter of any one or more of Examples 1-9includes, wherein each of the first and second phase-specific arcsuppressors comprises: a signal edge detector; an edge-pulse converterin series with the signal edge detector; a current limiter in serieswith the edge-pulse converter; and a first over voltage protectioncoupled to the edge-pulse converter and the signal isolator detector ofthe coil lock.

In Example 11, the subject matter of any one or more of Examples 1-10includes, wherein the edge-pulse converter is at least one of: atransformer; a pulse transformer; or a gate trigger.

In Example 12, the subject matter of any one or more of Examples 1-11includes, wherein each of the dual unidirectional arc suppressorsfurther comprises: a first contact terminal configured to beelectrically coupled to a first contact of the power contactor; a secondcontact terminal configured to be coupled to be electrically coupled toa second contact of the power contactor, the second contact terminalcoupled to the first phase-specific arc suppressor, the secondphase-specific arc suppressor, and the coil lock controller; and afusible element coupled between the first contact terminal and the firstphase-specific arc suppressor, the second phase-specific arc suppressor,and the coil lock controller.

In Example 13, the subject matter of any one or more of Examples 1-12includes, wherein the fusible element is one of: a solder mask, asilkscreen, a passive fuse, or an active fuse.

In Example 14, the subject matter of any one or more of Examples 1-13includes, wherein each of the dual unidirectional arc suppressorsfurther comprises a second over voltage protector coupled over the firstphase-specific arc suppressor, the second phase-specific arc suppressor,and the coil lock controller.

In Example 15, the subject matter of any one or more of Examples 1-14includes, wherein the second over voltage protector comprises at leastone of: variostor, a transient-voltage suppression (TVS) diode, a Zenerdiode, a gas tube, or a spark gap.

Example 16 is a three-phase arc suppressing circuit, comprising: a coilinterface, configured to be coupled to a contactor coil driver of apower contactor and to receive an output condition of the contactor coildriver and output a signal based on the output condition; a first dualunidirectional arc suppressor configured to be coupled to contacts at afirst phase, comprising: a first phase-specific arc suppressorconfigured to suppress arcing in a positive domain; a secondphase-specific arc suppressor configured to suppress arcing in anegative domain; and a coil lock controller, coupled to the coilinterface, configured to inhibit operation of the first and secondphase-specific arc suppressors over a predetermined time based on thesignal from the coil interface; a second dual unidirectional arcsuppressor configured to be coupled to contacts at a second phase onehundred and twenty degrees greater than the first phase, comprising: afirst phase-specific arc suppressor configured to suppress arcing in thepositive domain; a second phase-specific arc suppressor configured tosuppress arcing in the negative domain; and a coil lock controller,coupled to the coil interface, configured to inhibit operation of thefirst and second phase-specific arc suppressors over a predeterminedtime based on the signal from the coil interface; and a third dualunidirectional arc suppressor configured to be coupled to contacts at athird phase one hundred and twenty degrees less than the first phase,comprising: a first phase-specific arc suppressor configured to suppressarcing in the positive domain; a second phase-specific arc suppressorconfigured to suppress arcing in the negative domain; and a coil lockcontroller, coupled to the coil interface, configured to inhibitoperation of the first and second phase-specific arc suppressors over apredetermined time based on the signal from the coil interface.

In Example 17, the subject matter of Example 16 includes, wherein thepredetermined time is selected to allow the contactor coil driver tode-energize and allow time for the power contactor to break or makecontact.

Example 18, the subject matter of any one or more of Examples 16 and 17includes, wherein the first phase-specific arc suppressors areconfigured to not suppress arcing in the negative domain and the secondphase-specific arc suppressor is configured to not suppress arcing inthe positive domain.

In Example 19, the subject matter of any one or more of Examples 16-18includes, wherein each of the first and second phase-specific arcsuppressors comprise a latching switch configured to cause the first andsecond phase-specific arc suppressors to not suppress arcing in thenegative and positive domains, respectively.

In Example 20, the subject matter of any one or more of Examples 16-19includes, wherein the latching switch is a thyristor.

Example 21 is at least one machine-readable medium includinginstructions that, when executed by processing circuitry, cause theprocessing circuitry to perform operations to implement of any ofExamples 1-20.

Example 22 is an apparatus comprising means to implement of any ofExamples 1-20.

Example 23 is a system to implement of any of Examples 1-20.

Example 24 is a method to implement of any of Examples 1-20.

The above detailed description includes references to the accompanyingdrawings, which form a part of the detailed description. The drawingsshow, by way of illustration, specific embodiments. These embodimentsare also referred to herein as “examples.” Such examples may includeelements in addition to those shown and described. However, the presentinventor also contemplates examples in which only those elements shownand described are provided.

All publications, patents, and patent documents referred to in thisdocument are incorporated by reference herein in their entirety, asthough individually incorporated by reference. In the event ofinconsistent usages between this document and those documents soincorporated by reference, the usage in the incorporated reference(s)should be considered supplementary to that of this document; forirreconcilable inconsistencies, the usage in this document controls.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one, independent of any otherinstances or usages of “at least one” or “one or more.” In thisdocument, the term “or” is used to refer to a nonexclusive or, such that“A or B” includes “A but not B,” “B but not A,” and “A and B,” unlessotherwise indicated. In the appended claims, the terms “including” and“in which” are used as the plain-English equivalents of the respectiveterms “comprising” and “wherein.” Also, in the following claims, theterms “including” and “comprising” are open-ended, that is, a system,device, article, or process that includes elements in addition to thoselisted after such a term in a claim are still deemed to fall within thescope of that claim. Moreover, in the following claims, the terms“first,” “second,” and “third,” etc. are used merely as labels, and arenot intended to impose numerical requirements on their objects.

The above description is intended to be, and not restrictive. Forexample, the above-described examples (or one or more aspects thereof)may be used in combination with each other. Other embodiments may beused, such as by one of ordinary skill in the art upon reviewing theabove description. The Abstract is provided to comply with 37 C.F.R. §1.72(b), to allow the reader to quickly ascertain the nature of thetechnical disclosure. It is submitted with the understanding that itwill not be used to interpret or limit the scope or meaning of theclaims. In addition, in the above Detailed Description, various featuresmay be grouped together to streamline the disclosure. This should not beinterpreted as intending that an unclaimed disclosed feature isessential to any claim. Rather, inventive subject matter may lie in lessthan all features of a particular disclosed embodiment. Thus, thefollowing claims are hereby incorporated into the Detailed Description,with each claim standing on its own as a separate embodiment.

1. (canceled)
 2. A sliding power contact, comprising: a mobile loaddevice connector, comprising: a non-current power pin having a firstlength; and a current power pin having a second length less than thefirst length; a socket, configured to accept the mobile load deviceconnector, comprising: a non-current power contact configured toelectrically couple with the non-current power pin; and a current powercontact configured to electrically couple with the current power pin; anarc suppressor directly coupled to at least one of the non-current powerpin and the non-current power contact, wherein the arc suppressor, thenon-current power pin, and the non-current power contact form a currentpath between the current power pin and the current power contact whenthe non-current power pin is in contact with the non-current powercontact and the current power pin is not in contact with the currentpower contact; wherein the first length and the second length cause thenon-current power pin and the current power pin to contact thenon-current power contact and the current power contact, respectively,according to a predetermined sequence when the mobile load deviceconnector is inserted into the socket that causes the arc suppressor tosuppress arcing between the current power pin and the current powercontact.
 3. The sliding power contact of claim 2, wherein the arcsuppressor is a component of the mobile load device connector.
 4. Thesliding power contact of claim 2, wherein the arc suppressor is acomponent of the socket.
 5. The sliding power contact of claim 2,wherein the arc suppressor is a component of both the mobile load deviceconnector and the socket.
 6. The sliding power contact of claim 2,wherein the current power contact is a charged contact and the currentpower pin is a current collector.
 7. The sliding power contact of claim6, wherein the current collector is a commutator and touching thecommutator to the charged contact includes moving the commutator alongthe charged contact.
 8. A mobile load device connector, comprising: anon-current power collector having a first length, the non-current powercollector configured to contact a non-current power contact; and acurrent collector having a second length less than the first length, thecurrent collector configured to contact a charged contact; and an arcsuppressor directly coupled to at least one of the non-current powercollector, wherein the arc suppressor, the non-current power collectorand the non-current power are configured to form a current path betweenthe current collector and the charged contact when the non-current powercollector is in contact with the non-current power contact and thecurrent collector is not in contact with the charged contact; whereinthe first length and the second length cause the non-current powercollector and the current collector to contact the non-current powercontact and the charged contact, respectively, according to apredetermined sequence that causes the arc suppressor to suppress arcingbetween the current collector and the charged contact.
 9. The mobileload device connector of claim 8, wherein the charged contact is acatenary wire.
 10. The mobile load device connector of claim 8, whereinthe charged contact is a component of a third-rail system.
 11. Themobile load device connector of claim 8, wherein the current collectoris a commutator and touching the commutator to the charged contactincludes moving the commutator along the charged contact.
 12. A methodof making a sliding power contact, comprising: obtaining a mobile loaddevice connector, comprising: a non-current power pin having a firstlength; and a current power pin having a second length less than thefirst length; obtaining a socket, configured to accept the mobile loaddevice connector, comprising: a non-current power contact configured toelectrically couple with the non-current power pin; and a current powercontact configured to electrically couple with the current power pin;and directly coupling an arc suppressor to at least one of thenon-current power pin and the non-current power contact, wherein the arcsuppressor, the non-current power pin and the non-current power contactform a current path between the current power pin and the current powercontact when the non-current power pin is in contact with thenon-current power contact and the current power pin is not in contactwith the current power contact; wherein the first length and the secondlength cause the non-current power pin and the current power pin tocontact the non-current power contact and the current power contact,respectively, according to a predetermined sequence when the mobile loaddevice connector is inserted into the socket that causes the arcsuppressor to suppress arcing between the current power pin and thecurrent power contact.
 13. The method of claim 12, wherein directlycoupling the arc suppressor includes directly coupling the arcsuppressor to the mobile load device connector.
 14. The method of claim12, wherein directly coupling the arc suppressor includes directlycoupling the arc suppressor to the socket.
 15. The method of claim 12,wherein directly coupling the arc suppressor includes directly couplingthe arc suppressor to both the mobile load device connector and thesocket.
 16. The method of claim 12, wherein the current power contact isa charged contact and the current power pin is a current collector, andwherein forming the second current path between the current powercontact and the current power pin comprises touching a charge collectorto the charged contact.
 17. The method of claim 16, wherein the chargecollector is a commutator and touching the commutator to the chargedcontact includes rolling the commutator along the charged contact. 18.The method of claim 17, wherein the charged contact is a catenary wire.19. The method of claim 16, wherein the charged contact is a componentof a third-rail system.
 20. The method of claim 16, wherein the currentcollector is a commutator and touching the commutator to the chargedcontact includes moving the commutator along the charged contact.